The present invention relates to an ignition apparatus for an internal combustion engine particularly suitable for use with a motorcycle for preventing the theft thereof.
A typical example of a known ignition apparatus will be described below with reference to FIG. 8. In FIG. 8, the known ignition apparatus illustrated includes a switch unit 2 having a key switch 20 connected via a junction b to a battery 1, a power circuit 30 connected via a junction a to the key switch 20, and an ignition control unit 3 having a controller 31 in the form of a central processing unit (CPU) connected to the power circuit 30. The battery 1 generates a voltage of 12 volts for example, and the power circuit 30 reduces the source voltage of 12 volts to 5 volts for example.
In operation, the key switch 20 of the switch unit 2 is turned on and off to control the power supply to the CPU 31 for performing ignition control on the engine.
In this connection, if the switch unit 2 is disconnected for some reason such as by a thief the junctions a and b are directly connected or "hot wired" to each other, power is supplied to the ignition control unit 3 from the battery 1, and the engine can be started under the control of the ignition control unit 3. That is, the engine can be started in an easy manner without the need of the engine key or the key switch 20.
Thus, with the above-described known ignition apparatus for an internal combustion engine, there is a problem that the engine can be started very easily without the operation of the switch unit 2.